Coordinated speed and pressure control apparatus for combustion engines



May s, 1951 PARROW 2,551,979

H. T. YS COORDINATED SPEED AND PRESSURE CONTROL APPARATUS FOR COMBUSTION ENGINES B, y2/VM@ rifa/MU May 8, 1951 H. T. sPARRow 2,551,979

cooRmNATEn SPEED AND PRESSURE CONTROL APPARATUS RoR coNEusTIoN ENGINES f-RDLL AXIS May 8, 1951 H. T. sPARRow 2,551,979

- COORDINATED SPEED AND PRESSURE CONTROL APPARATUS RoR coMEuSTroN ENGENES Filed April 5, 1946 v 3 Sheets-Sheet 3 l5 rH 1 7* M .T"| 2L ELECTRNRL Conway l cmeuws A STREAM IN V EN TOR.

HUBERT T SFARRw mE/15X STA-nc -5. PRESSuR E Patented May 8, 19,51

COORDINATED SPEED AND PRESSURE CON- TROL APPARATUS FOR COMBUSTION EN- GINES Hubert T. Sparrow, Minneapolis, Minn., assignor to Minneapolis-Honeywell Regulator Company, Minneapolis, Minn., a corporation of Delaware Application April 3, 1946, Serial No. `659,261

23 Claims.

This invention relates to improvements in power control apparatus for combustion engines, and particularly to control apparatus for the engines used in aircraft.

The primary object of the invention is to provide for the pilot, or engineer, a single control member by which the speed and intake manifold pressure of such an engine may be controlled in a certain and predetermined sequence and with a rate of change of both factors in accordance with the known optimum operating charactertistics of the individual engine.

Aircraft engines are conventionally provided with turbine driven supercharging compressors, or turbo-superchargers as they are known, to provide a controllable supply of air under pressure for admixture with the fuel and admission to the intake manifold of the engine. To meet the changing conditions of atmospheric pressures encountered at different night levels the rate of compression of the air is controlled by adjustment of a waste gate regulating the differential pressure of exhaust gases from the engine across the turbine, said gases being employed for operating the turbine in accordance with conventional practice. To regulate the effective intake manifold pressures the aforesaid waste gate is positioned as required While in addition the usual throttle is employed as a further control, the latter particularly where the boost afforded by supercharging is not required. The engine speed is determined by the setting of a variable pitch propeller controlled by a propeller governor.

Thus it is evident that the effective power output of the engine, being a result both of engine speed and the intake manifold pressure which determines the volume of the combustible mixture fed to the engine, is regulated by no less than three separate controls, namely, the throttle, Waste gate and propeller speed governor. It is further to be understood that, for each type of engine, there is a known relative value of engine speed and intake manifold pressure under all conditions which, if maintained, will result in optimum power output and maximum efficiency from the propeller.

Having in mind these facts,vit is a further and important object of my present invention to provide a single lever or single member control for an aircraft engine by which engine speed and intake manifold pressures may be conveniently controlled and selected in accordance with the known varying relative values of each, to secure at all times the optimum eiciency from both engine and propeller, and this without requiring that the pilot calculate and adjust the various controlling factors independently.

A further object is to provide a control system of this nature wherein the throttle remains under control of the manual selector member at all times so that the pilot may close the throttle and override the control system as a whole in an emergency. An auxiliary object in this connection is to provide a throttle control mechanism wherein is embodied a floating member positioned in accordance with the manually selected position of the single control lever, permitting the throttle to be opened as the engine is first set in operation, but providing flexibility such that the control lever may be further moved in a throttle opening direction for controlling engine speed and waste gate position, while retaining mechanical connection with the throttle.

Still another object is to provide in an engine control system of the character set forth, a means responsive to engine speeds for selecting the optimum value of intake manifold pressures for such speeds.

Still a further object is to provide an aircraft engine control system wherein operation of the single control lever or member during certain ranges thereof is made eective to select air4 speeds by means of an air speed controller which controls the engine speed which in turn regulates the intake manifold pressure. In this manner the air speed of the aircraft is made effective to control engine speed and the latter is automatically adjusted to optimum values for take-off and landing operations, but as soon as the air speed reaches a value suicient to satisfy the conditions called for by the manually selected position of the control lever then the value of engine speed and intake manifold pressures thus called for will be immediately achieved and maintained.

Other objects and advantages of my invention will become apparent from a consideration of the appended specification, claims and drawings, in which:

Figure l illustrates diagrammatically a complete engine control system embodying my invention,

Figure 2 is a similar showing of certain parts of the system but under different conditions of operation,

Figure 3 is a chart illustrating roughly the effect on engine speed and intake manifold pressure brought about by my control system and indicating the function of the single control member by which these factors are controlled,

Figure 4 is a fragmentary diagrammatical assegni output is being controlled, the main components of Figure 1 being shown in block diagram form in this Figure 6, and

Figure 'l shows one possible way in which the air-speed controller of the Subj ect apparatus may be constructed.

Referring now more particularly toFigures l and 6, I show therein a complete control system for positioning and controlling a throttle 5, a Waste gate 6, and a propeller governor l, allof conventional form. The throttle 5 as usual controls the ow of air to and through a carburetor C to the engine E (shown in Figure 6) and regulates the volume or weight of the combustible mixture supplied to the engine. The waste gate 6 controls the flow of exhaust gases flowing from the engine exhaust manifold EM to an outlet 8 and as the gate is progressively closed an increasing volume of the gases is directed through a duct or nozzle 9 to a turbine I@ to increase the speed thereof as will be evident. rIhe governor 'I regulates the pitch of a Variable pitch propeller II which is driven by the engine for the usual purposes, the governor acting to maintain the propeller speed for which it is set.

The turbine I operates a compressor or supercharger I2 which receives air at atmospheric pressure through an intake I3 and delivers the air under pressure through an outlet conduit Ill and inter cooler IC (shown in Figure 6) to the engine, under further control of the throttle 5. The compression ratio of the compressor I2 is determined by its speed and hence the Waste gate 6 affords very precise control of the pressure of the air delivered by the compressor.

For controlling and positioning the throttle 5, waste gate 6 and propeller governor I, and accordingly controlling the engine speed and power, I provide an electro-mechanical system embodying as a primary controller a single lever or member I adapted, as here shown, to be moved over an arcuate member I6 by hand from the indicated low power or initial position through three ranges designated in the drawings as ranges I, 2, and 3, toward a maximum power position.

Referring to Figure 6, the lever I5 is shown operatively connected to the mechanical camming apparatus lVi which in turn is coordinating the adjustment of the propeller governor 'I through appropriate connecting means II8, an air-speed controller I22 through connecting means i2@ and adjusting lever |23, the throttle 5 through connecting means 22, 2t, and 2l and the electrical control circuits EC through connecting means lil. All of the connecting means have been shown in dotted lines and the direction of the arrows on the dotted lines indicate the direction the control travels over the connecting means. Also adjusting the control circuits ECare control signals originating from a device VA responsive to the speed and acceleration of the turbine It connected to the control circuits EC by connecting means SC, a vertical gyroscope Iil connected to the control circuits by connecting means VG, `and a propeller speed sensing device I26 connected to the control circuits by connecting means PS. Aiurther control signal for the circuits EC is derived from '.ductors 46 and ell.

the pressure on the intake manifold IM of the' engine E through a pressure sensing duct 9E). The output control from the electric control circuits EC serves to position the waste gate 6 through connecting means 35 and the throttle 5 through connecting means 32, 2B andZ'I. Reference should bemade to Figure 1 and the discussion that follows to understand the details of construction and functioning of the control apparatus.

Referring again'to Figure l, movements of the control lever I5 obviously will oscillate a shaft Il whereon it is supported, thus moving a pressure selector wiper I8, a disk i9, a cam 20 and a cam 2l all of which are attached to said shaft. In addition, the control lever i5 positions the throttle: E through a linkage mechanism comprising arst link 22 pivoted at one end at 23 to the lever, a second swinging link or lever 2li pivoted at one end ati25 to the other .end .oflink-ZZ, and a third link 26 pivoted at 21a to the other end of link 2d, the remaining end of the third' link 2.6 being pivotally attached to the usual crank '2l for swinging the throttle 5 in its induction system conduit23. The swinging link 24 is, furthermore, fulcrumed at 29 upon one end of a floating bar or supporting link member which is axially shiftable in supports 3l by means of a pinion 32 engaging rack teeth 33 on the bar. The exact nature and purpose of this shiftable or iloating support will 'be presently made clear.

The waste gate 6 is driven by a motor 34 through a gear train 35. The moto-r 3ft is of the split phase type, being provided with a pair of field wndingsft and 3l which are spaced 90 electrical degrees apart, and an armature 33. The field winding 3l is supplied with electrical energy from a secondary winding 3Q of a transformer liu having a primary winding 4I which is connected to a suitable source (not shown) of alternating current. The energizing circuit for the winding 31 may be traced from the right hand terminal of the transformer winding39 through a conductor ft2, a condenser lli-3, the eld winding 3l, and a conductor 44 to the left hand terminal of the secondary winding 39.

The flow of electrical energy to the motor field winding 36 is controlled byv an electronic amplier 45 to which the winding is connected by con- The amplifier 'd5 is powered from another secondary winding i8 on. the transformer 50, to which the amplifier is connected through conductors t9 and 5t.

The amplier t5 is provided with a paii` of in- 'put terminals 5i and 52 and operates to supply the field winding 36 of the motor with alternating current the phase of which depends upon the phase of an alternating current signal impressed across these input terminals 5I and 52. Any common form of amplier in which the` phase of the output voltage reverses'with a reversal of the phase of the input voltage may be used. A suitable amplier of this type is shown in Figure l of the copending application of Albert P. Upton,

Serial No. 437,561, filed April 3, 1942, now Patent No. 2,423,534issue.d J uly'S, 1947.

It will be evident that if the motor field winding 36 is supplied with alternating current which leads the current in the other field winding ill by ninety electrical degrees, the motor will rotate in one direction, whereas if the current in winding 36 ylags the current in winding 3l by this. amount, the motor willrotate in the opposite direction.

- 1 The phase of the signal applied to the amplifier input terminals 5I and 52 is determined by the electrical conditions existing in a compound network which consists of vc networks connected in series. Of these iive networks, designated generally at 53, 54, 55, 56 and 51, the latter may be connected in, or eliminated from the series circuit by means of a single pole, double throw switch 58 having a center blade terminal 59 and spaced blade terminals 66 and 6l. For convenience this switch will be considered rst as so positioned that the network 51 is cut out of circuit, the circuit being completed through the switch blade between the terminals 59 and 6U as seen in Figure l. Bearing this in mind, the circuit may be traced from the amplifier input terminal l through a conductor 62, the network 53, a conductor 69, the network 54, a conductor 64, the network 55, a conductor 65, the network 56, a conductor 66, the switch 58, and a conductor 61 back to the other ampliiier input terminal 52.

The network 56 includes a transformer secondary winding 66 across whose terminals are connected two series potentiometer or slidewire resistances 69 and 19 by means of conductors 'H and 12. The transformer carrying secondary winding 68 is shown as having a primary winding 266. The resistance 69, connected at one end by conductor 1I to the right hand terminal of winding 66, has also a conductive portion 13 which is connected by a conductor 14 to one end of the resistance 19, the other end of which is connected by aforesaid conductor 12 to the left hand terminal of winding 68. Said conductor i4 is also connected to a center tap on winding 68. Cooperating with the resistance 69 and its conductive portion 13 is the wiper i8 operated by the control lever i5 and the advance movement of said lever is seen to cause this wiper i8 to transverse rst the resistance 69 and then the conductive portion 13. The wiper thus varies in potential, with respect to winding 68, while travelling the resistance 69 but maintains a fixed p0- tential, dependent upon the magnitude of the whole of this resistance 69, while traversing the length of the conductive portion 19. In practice the slider I8 traverses the whole length of the resistance 69 while the control lever l5 moves through range l, previously referred to, and travels along conductive portion 13 while the lever moves through ranges 2 and 3.

Cooperating with the resistance 10 is a wiper 16 which is positioned by a propeller speed responsive controller 26 as will be discussed later. This wiper 16 is connected in circuit during the third or final range of advance movement of the control lever l5 by means of a snap acting changeover switch shown schematically as comprising a swinging blade 11 to which conductor 96 is connected, and a pair of opposed contacts 18 and 19. Contact 18, into engagement with which the blade 11 normally is urged by a biasing spring 11a, is connected by a conductor 86 to the wiper I8 and thus the circuit is normally completed to the network 56 through this wiper. Contact 19, on the other hand, is connected through a conductor 8l to the wiper 16 and the changeover switch is so located with respect to the disk i9 on the control lever shaft I 1 that a nger 92 thereon will engage the switch blade 11 and oscillate it into engagement with contact 19 immediately as the control lever l5 enters its third or nal range 3 or" advance movement. Either the switch blade 11 is made resilient or some strain release means is provided to permit continued movement of lever l5 through range 3 after engagement of blade 11 with contact 19.

Thus, during this range the slider 'I6 will con# trol the potential produced by network 56 independently of control lever adjustment. As the lever is pulled back, the changeover switch will resume its normal position here shown by reason of the biasing action of spring 11a and manual control will be reassumed by the slider I3.

Another slidewire resistance 89 is connected across one half of the winding 68 by a connection at its ends between the conductors 1l and 14, leading respectively to the right hand terminal and center tap of this winding. A slider 84 cooperates with this resistance 83 and together therewith forms a calibrating potentiometer 8 5. The connection between the center tap 15 of the winding 68 and the junction of the primary and secondary pressure selector controller potentiometer formed, respectively, by the slider i8 and resistance 69 and by the slider 16 and resistance 19, reduces the impedance between these sliders and slider 84 but does not otherwise affect operation of the network.

The network 55 comprises a transformer secondary winding 86 across the terminals of which is connected a slidewire resistance 31 as clearly shown. This transformer also has a primari7 winding 286. Cooperating with resistance 91 is a slider 63 and together these elements comprise a pressure controller potentiometer 91 which is adjusted in accordance with the pressure of the air delivered to the engine. For this purpose a bellows 69 is connected by a pressure line 99 to some point in the induction system between the compressor l2 and the engine, preferably the vintake manifold of the engine (as indicated by a legend in the drawing), so that this bellows senses intake manifold pressure. An evacuated bellows 9i is provided and the two bellows are supported with their free ends at opposite sides of, and connected to, the slider 89 so that the same is positioned along resistance 81 by pressure changes. The bellows 9i compensates this controller for atmospheric changes in a well known manner. The conductor 65 connects sliders 84 and 88.

A second slidewire resistance 92 is connected as shown across the transformer secondary winding 86 and cooperating with this resistance is a slider 93 which is positioned by an acceleration responsive controller 94 connected to the turbine I9. Normally said slider 93 rests upon a conductive spot 95 on resistance 92, so that minor accelerations will have no eiect on the system, but the controller 94 operates to swing slider 93 across the resistance in response to over-acceleration of the turbine. Said resistance 92 and slider 93 thus cooperate to form an acceleration limiting or compensating controller potentiometer 96.

'I'he network 54 comprises a secondary winding 98 on a transformer, having a primary winding 299, and a slidewire resistance 99 is connected by a conductor 109 to one terminal of winding 96 and by a conductor mi to a tap 92 on the winding. A slider H99 cooperates with the resistance 99 and is positioned therealong by con nection to a velocity responsive controller dell which is driven by the turbine l El. The resistance 99 and slider H93 together form a velocity limiting or compensating controller potentiometer E65 which is adjusted in accordance with turbine velocity, the controller 64 operating to move the slider across the resistance when the velocity exceeds a safe maximum value. The conductor 64 connects the sliders 99 and ID3.

The :network "Slialso includesa slidewre resistance l, thet left hand .terminal-.of .which `is connectedby azconductor ll to the tap 162 von winding and ther-ighthand'terminallof which is connected .by a .conductor H18 to the correspending end terminal of the winding '38. Cooperating with the resistance lis a -slider 109 and together these elements :form a waste gate follow-.up potentiometer lill. The slider ItV is moved. Aalong resistance 106 by connection to 'the aforesaid gear train .35 and the slider movement is thus concurrentwithand proportionalto that of .thewastegate 6.

Thegne'twork 53 comprises a secondary winding H1 on a transformer having a primary'winding 311 and across .the terminals of winding ill is connected Ya slidewire resistance 112 bymeans of conductors liz3 and 1li. Cooperating with the resistance H2 is a manuallymovable slider .6.1.5 andr together therewith the slider forms an overlap controller potentiometer 116, the purpose of which will later appear. The conductor 53 :connects .the sliders 1629 and 11.5, while conductor .62 leading to amplifier input terminal 5| is connected to one end of the secondary winding 1 1 i.

Thepropeller governor 'l is adjusted directly by control lever lidu-ring therst range of advance movement thereof. -For this purpose there is shown., for example, a crank i il on the governor 'l to which is connected a link 118 operated by a lollower 1li] riding the cam 21. Said cam is so shaped that, during such first movement of the lever l5 and its shaft 1l, the Aresulting oscillation of the cam will actuate the link H3 and swing crank ill whereas continued movement of the cam will have no controlling eiiect upon the governor. For the remaining two ranges of movement of the control lever i5, the .propeller governor '1 is adjusted by a reversible electric motor 20 through a gea-r train 1-21. Said motor is in turn controlled by an air speed controller 122 which, for example, is shown as regulated by a crank 12? to whichl is` connected. a link 125i having a follower $.25 engaging cam 29. This cam 25 is then so formed that the initial movement of the cam, while control lever 15 moves through its rst range, will have. no effect on the air speed controller, vwhile continued movement or the control lever through second and `third ranges will adjust the air speedeontroller to .select increasing air speeds. Such adjustment o'i controller 122 will then control. motor i'21l to adjust the propeller governor l and control the pitch of the propeller 1l as required. .The propeller governor 'l may be of any conventionalform.

rThe air-speed controller may be of any "conventional form, such as is shown in Figure 7. The apparatus shown in Figure 7 is basically the same as a patent to Reichel, No. 2,363,143, issued November 2l, 194i, with electrical contacts associated vwith the lair-speed indicating arm andY with the adjusting screw actingas the air-speed selector. Referring to Figure '7, an intake air scoop is indicated at 225. Thisis exposed tothe air stream along the forward line of ilight of the craft. A conduit 226 is provided tosupply a static air pressure to the subject controller. Located within the housing 122 is .a bellows 221 which has the dynamic pressure from .the air scoop 225 applied to the inside thereof and has the static pressure from conduit 226 applied to the outside thereof. The bellows is resiliently supported by an adjustable blade 228, which is adjustable by adjusting means 229. The `output arm of the bellows positions a floating lever f thephase of which is determined 230 iibetweenzapairzoi contacts' '-23.1 :and 2321associated .with a vthree wire electrical control circuit. Movement :of .the .adjusting mechanism toward the left-...has the effect of increasing the air speed selectedwhile movement, towardthc right has the eiiecty of .decreasing `the air speed selection. While-an airscoop has been `shown in Figure '7., the conventional Pito't tubes, as shown in the Reichelfpatent:may ybe substituted therefor.

It :may here be noted, .referringto Figure 1, thatthe i'lrst,..second. and thirdxrangesoi movementoi control lever ,1'5- are. used merely. for convenienoeindescription:anddisclosure Actually, of course, there will bei no welldeiined or :limited rangesof movementuof. thelever.

There .is .also provided a controller lresponsive to `the .engine or propeller speed, designated at 126,.1and .whic-his driven, forexample,` by atachometer connection to the propeller shaft. This controller, be.. it. iiyi-ball lgovernor type `or otherwisepisrarrangedto position theslider 'llalong the resistance '1B :as the enginespeed increases above a predetermined. minimum. inasmuch as the fsliderl and. resistance i0 are cut into circuit only .during the later advance movement of the control lever 15, the engine speed at which the controller'12 becomes eiiective to .shift the slider will -necessarily be afairlyhigh, and one corresponding to a desirable engine speed for the intake .manifold pressure .selected by the preliminary movements of thelever.

The pinion 32 hereinbeiore described, for axially adjusting. boating member ,3 El. visaCtuated by. a reversible,electricmotor 1.2i througlfna gear train 12B.. .This .motor 12? is ofthe vsplit .phase ty.pe,.lil e motor 34, and has; a. pair of eldwindings 129.V and 1.30. spaced ninetyy electrical degrees apart, andan armature 131. The field winding 25 is .supplied with.'electrical energyA ironia seoondary winding 132 .oa transformer 13sv havirle a .primary 134. .The .energiaingcircuit for this iield winding .129 .may be traced from. a .lower terminal v.of secondary winding .132 through a conductor 135, yacondenser 1136.,..the vwinding .-129 and a conductor 137 to the .upper terminal .of winding E32.

The Vflow oi Yelectrical .energy to the other neld winding 131i! iscontrolledby an :electronic amplifier 133 to whi'chfsaid windingis connected by conductors 13e .and im. This amplifier is powered vby another secondary winding 1411 of transformer. SL35 to which winding the ampliiier is connectedrby conductors ifi-2 and l143. .'.'he amplier :138 -is provided with a pair lof input terminals :1111i and wie `and operates to supply motor field winding ESS with alternating current of a signalpotential applied across the terminals lili and M5. The amplifier i'33 thus operates to control the motor ii'i 'exactly as the previously described amplifier '45 controls the waste gate motor 311 and no *further description shouldbe required at this point.

The input terminalfEll-ii oi the amplifier 133 is connected to the input'terminal 52 of th `arnplier @-5 andxior :convenience in illustration such connection is ,showin as made by ground connections indicated at it and i'l.

The signal potential applied. to the amplier 133 is determinedin part by the compound series network previously described but in addition by a separate network Itfi and a controller 1e@ forming part oi the network 5i. The energizing or signal input circuit -for amplifier traced from the terminal 144 through a conby the phase 138 may be` ductor |58, the network |48, a conductor I|, the controller |49 and network 54, the conductor 84, network 55, conductor 65, network 56, conductor 85, switch 58, conductor 61 and grounds |41 and |4313 back to the other input terminal |45.

The network |48 comprises a transformer secondary winding |52 across the terminals of which is connected a slidewire resistance |53 bymeans of conductors |54 and 55. The transformer carrying winding |52 has also a primary winding 352. Cooperating with the resistance |53 is a slider |55 positioned by a reversible, throttle reset motor |51 through a gear train |58. The resistance |53 and slider I 58 together form a throttle reset controller, controlling amplifier 35;

The controller |49 comprises a slidewire resistance |58 connected in parallel with the followup resistance |85 by conductors ISI and I 82 and cooperating with said resistance is a slider |63. The slider |63 is operatively connected through a connection |63a to the gear 32 so as to assume a position corresponding to that of throttle motor |21. The resistance |68 and slider |53 together form a rebalancing potentiometer or controller.

The motor |51 is of the split phase reversible induction type having a pair of eld windings |84 and |65 spaced ninety electrical degrees apart, and an armature |58. The field windings |54 and |55 have a common terminal |81 connected to one terminal of an inverter |68, or other suitable source of alternating current electrical energy, and between the other terminals of the windings is connected a condenser ISS. other terminals of the eld windings |64 and |65 'are further connected by flexible conductors |18 and |1|, respectively, to slider or chaser contacts |12 and |13. These contacts |12 and |13 are carried in spaced relation upon an insulating base i'g'll ailixed to the link 25 of the throttle adjusting linkage and are adapted upon opposite movements of said link to make selective contact with a fixed center contact |15, to which the other terminal of the inverter |58 is ccnnected by a conductor |16.

It will be evident that when the link 28 is moved to the right, in 1Figure l, far enough to bring Chaser contact |12 into engagement with center contact |15 a circuit will be closed to motor iield winding |55, which may be traced from the ripper terminal of the inverter |58 through the conductor |15, contacts |15 and |12, conductor il, through winding |68 and through conductor |51 to the lower terminal of the inverter. This lield winding ESQ is thus energized directly by the inverter |88 and the votlage at the winding is of course in phase with that at the inverter. At the same time, the other motor field winding is energized. and the circuit may be traced from the upper terminal of the inverter through the conductor |16, the contacts |15 and |12, the conductor |18, the condenser ESS, the field winding |55, terminal |81 and back to the lower terminal of the inverter. The ccndenser |88 is thus in circuit with this winding and the electrical effect thereof is to cause the voltage ni this winding to lead that oi the int and the other held winding |68, by one ar l,fcle or ninety electrical degrees. As a result, the noter armature |58 will rote-te in one direction long as the contacts |12 and |15 remain in engagement.

When the link 25 is shifted to the left in Figure l to a point bringing the Chaser contact |13 into engagement with contact |15, the condtiions are reversed, the field winding |65 being now directly energized from the inverter |68 while the eld winding |64 is energized through the condenser !69. The motor will thus rotate in an opposite direction as long as contacts |13 and |15 are engaged. The energizing circuit for winding |55, with contacts |13 and |15 engaged, may be traced from the upper terminal of the inverter |68 through the conductor |18, contacts |15 adn |13, condctor I1|, winding |85 and terminal |81 to the lower terminal of the inverter. The circuit for winding |64 may be similarly traced from the upper terminal of the inverter through conductor |18, contacts |15 and |13, conductor |11, the condenser |59, winding |84, terminal |81, and back to the lower terminal of the inverter.

The operation of the motor |51, and its direction of rotation when operating, is thus seen to be controlled by the position of the link 2S and thereby is determined by the position to which the throttle 5 is adjusted.

Operation In this description of the operation of my system as shown in Figure 1, reference will also be had to Figures 2 and 3.

It will nrst be understood that all of the primary windings 4|, |8I, |34, 268, 286, 288, 3|I, and 352 are connected to a common source of alternating current, or the various secondary windings are on a common transformer, so that the alternating potentials at the terminals of the secondary windings are in phase with each other. The signal potentials applied across the input terminals of the amplifiers 45 and |38 are, of course, the algebraic sums of the potentials developed in the associated series networks.

Considering rst the operation of the compound network controlling the waste gate amplifier 45, it will be noted that I have indicated the polarities oi the networks 53, 54, 55 and 56. Thus, the potential conditions existing during a half cycle when the polarities are as indicated will be described, for convenience, and for a reference potential the conductor 61, leading to amplifier input terminal 52 is shown as grounded at |41, or of zero potential.

With the control lever l5 in minimum power position, as seen in Figure 1, the slider i8 is at the positive end of the resistance B9, On the other hand, the slider 84 is at an intermediate point along the resistance 83 and so is at a negative potential with respect to the slider I8. Since slider I8, leads 80, 66, and 61 are all grounded it will be seen that network 56 under these conditions introduces a potential into the series circuit conneoting the input terminals of the amplifiers such that the conductor 85 is negative with respect to grounded conductor 61.

Turning now to the network 55, it will be seen that, with the sliders 88 and 93 in the positions shown, this network introduces into the series circuit a potential determined by the potential of slider 88 relative tothe potential of the left hand, positive terminal of the secondary winding 86. This potential is of a polarity such that the slider 93 is positive with respect to slider 88. The positive potential thus developed in network 55 opposes that produced in network 58 and the potential on conductor 64, with respect to grounded conductor 61 is the diierence of the potentials developed in the two networks thus far discussed. It will be assumed that thevoltage same -potential with respect to each other, being each directly in contact with the tap |52 on secondary winding 98. For purposes of this discussion the network 54 may be considered as devel-- oping no potential in the series circuit and the conductor 63 is therefore at the same potential as grounded conductor 6l.

Turning last to the Ynetwork 53 it will be evident that With the slider H in the'postioll4 shown, the conductor 52 is negative with respect to slider ||5 and the conductor 53. The magnitude of the negative potential thus introduced into the series circuit is determined by the position ofA `the slider ||5 along the `resistance H2. Since conductor 53 is at ground potential, the conductor e2 is negative with respect to ground by the amountof the voltage introduced by network 53. Under such lconditions the compound network is unbalanced and there is appliedV between the amplifier,` inputterminals 5| and 52 a voltage such that terminal .5| is negative with respect .to terminal 52.

The signal potential applied to the amplifier V||5 under these conditions is of such polarity that. thcamplier .supplies energy to the waste gate motor winding 36 of such phase with respect to that .Suppliedto winding 3l that the motor 54 attempts to drive the waste gate 6 towards open position. Since the wastegate E is already completely open, the motor simply exerts a ktorque against, alimiting stop means (not shown).

Consideringy now the network conditions controlling the amplifier |38, it will first be understood that the `input terminal |45 isgrounded or atthe same ,potential as conductor lil. Thus, conductor Y61|Y Yis at the same potential as the groundedinput terminal |45. Tracing through networks 54 and |48., it is to be noted that rebalance slider |53 is at the extreme'left hand end f.

o fresistor |60 so tthat no voltage existsbetween conductor 5,4 and slider |63. Hence, conductor |5| is likewise at ground potential. Referring now to the network |43, it is to be noted that slider |56 is in its extreme right hand position l s o thatY no voltage is introduced by network |48. Thus, conductor |55 leading to the input terminal |44 is at ground potential. Under these conditions, no'voltage is supplied to the input terminal of the ampliiier and the field windinef vIii!) is deenergized. VAs, a result, the motor |21 is deenergized.

Fortlie presentythe effect of the movement of 'the-sliders' 84, 93, |03, and l5 upon the amplifiers 45 and |38 will be ignored, particularly since these are essentially calibrating, or adjusting, and protective controls.

Assuming now that the engine is started up and the control lever I5 is `advanced in range of its movement, the slider-I 8 is moved away from the positive end of the resistance 69 having an immediate eiect on the potential conditions in the series circuits as they are controlled by the 'f network 5S. Still considering the operation under conditions whereat the polarities and potentials are those heretofore described, the effect of this movement ofthe slider I8 is seen to be a decrease in the negative potentialat conductor 65 with respect to conductor 6l. This results in a reduction in the negative voltage between teractieve l2 minals 5| and 52. Since the unbalance voltage is still of such a phase as to cause the lwaste gate to run towards open position and since the waste gate is already fully open, no movement of the waste gate takes place.

The aforesaid movement of the control lever l5 also is translated mechanically to an opening movement of the throttle 5, it being evident that the endwise movement of the link 22 and resulting swinging movement of the link 24 about pivot 29 causes link 26 to shift to the left and open the throttle.

The rotation of the cam 2l by this movement of the control lever i5 also actuates the link ||8 to adjust the propeller governor l, causing the pitch of the blades of the propeller to be changed in such manner as to bring about a progressive increase in engine speed. The air speed controller |22 is not, however, adjusted during this portion of the movement of the control lever |5 as has been previously pointed out. While the movement of slider le over potentiometer 55 tends to make the conductor |50 and terminal 'ieri positive with respect to terminal |45, this effect is largely overcome b-y the increase in manifold. pressure resulting from the opening of the throttle 5. This increase causes slider 88 to move to the left with respect to resistor Bl and o hence to make conductor |55 negative with respect to ground. At low altitudes, the change in the effect of network 56 due to movement of the slider i8 and that in network 55 due to the movement of slider 88 as a result of the increase in manifold pressure may exactly balance each other. At higher altitudes, however, the manifold pressure will not rise enough for the signal introduced by the increase in manifold pressure to balance out the signal introduced by movement of slider i8. Hence, conductor and terminal lllbecome positive with respect to terminal |45. The phase of the signal applied to the amplifier under these conditions is such that a current is supplied to winding i 30 of such phase as to cause motor |21 to drive link 3B to the left. Since the pivot point 25 is stationary, this causes movement of the link 26 to the left to cause an opening movement of throttle 5. At the same time, the slider 53 is moved by motor |21 to the right to cause slider |53 to become negative with respect to conductor lil! and hence to introduce a rebalancing voltage tending to make conductor less positive with respect to ground. The opening movement of the throttle will increase the manifold pressure even more, reducing the unbalance voltage. When the motor |21 has moved to a position at which the rebalancing voltage introduced by bridge |49 is equal to the reduced unbalance voltage, the potential of input terminal |54 of amplifier |38 will again be the same as that of grounded terminal |55 so that the motor |21 stops its rotation. Any tendency of the manifold pressure to increase, assuming all other things to remain the same, will cause a movement of slider 88 to the left to cause the input terminal |54 of amplifier |33 to become negative with respect to the grounded terminal |45. This causes an opposite effect to that considered, namely operation of motor |21 in a direction to close the throttle.

As the lever l5 is moved to the right through range l, a point may be reached at which the throttle 5 becomes fully open, and further movement of lever I5 is temporarily prevented by a stoppin Il engaging the throttle crank arm 21. The point at which lever I5 is stopped depends 13 upon the position of throttle motor |21 which in turn is dependent upon the manifold pressure. When this happens, contact |15 engages chaser contact |13 to establish an energizing circuit to motor eld windings |64 and |65, as previously traced. The direction of rotation under these conditions is such as to cause the motor |51 to move slider |55 to the left so as to cause conductor |53 to become negative with respect to conductor |I. This causes conductor |50 and terminal |44 to be negative with respect to terminal |155. It will be recalled that the elect of this type of unbalance is to cause the throttle motor to operate in such a direction as to close the throttle. As soon as the throttle starts moving towards open position, however, the chaser contact |13 separates from contact |15 to interrupt the circuit previously traced. The movement of the throttle motor |21 causes slider |53 to be moved back towards the left to increase the potential of conductor |5| in a positive direction and hence to rebalance the series of networks connected to amplifier |38 thus stopping further movement of the throttle in closing direction. With the throttle slightly closed, it is possible to move the lever 5 still further to the right. This causes reengagement of contacts |13 and |15 and the process just described is repeated. Thus, upon continuous pressure being applied to lever |5, the Chaser contacts |13 and |15 are continuously engaged with the throttle motor continually operating to shift the lever 24 to permit movement of lever 5 with the throttle in full open position. Thus, the elect of the throttle reset f motor |51 is to permit a continued adjustment of lever |5 in throttle opening direction after the throttle has reached full open position. .The reason for this is that the operation cf the control system demands the movement of lever I5 throughout its entire range of movement despite the fact that under certain circumstances the throttle may be moved to full open position before the lever |5 has moved through range I of its movement. With this arrangement, the lever |5 is at all times mechanically connected to throttle 5 so that the throttle can at any time be manually moved to any desired position.

Whenever the pressure controller 91 is not satised by a movement of throttle 5 to a position approximating full open position, the waste gate motor 34 is placed into operation to start moving the waste gate towards closed position. It will be recalled that under the conditions previously described, the eilect of bridges 53 and 56 in tending to make terminal 5| negative with respect to grounded terminal 52 was greater than the eiect of bridge 55 in tending to make the terminal 5| positive with respect to terminal 52. As slider I8 is moved in a clockwise direction, however, the negative voltage introduced between conductors 65 and 8!! decreases. This is overcome to some extent by the movement of slider 38 towards the left as higher manifold pressures are maintained. As slider I8 is moved in a clockwise direction, however, a position is soon reached where the effect of bridges 53 and 56 just balances the eifect of bridge 55. Let it be assumed that either the slider |8 is moved further or that the intake manifold pressure drops so as to cause the movement of slider |8 towards the left. In either oase, the effect is to cause conductor 62 and hence terminal 5| to become positive with respect to terminal 52 instead of negative as has been previously the case. When this happens, the signal supplied to ampliner 45 is of such phase as to cause energization of motor 34 in a direction to move the waste gate towards closed position. This is accompanied by a movement of slider |09 to the right so as to make slider |63 increasingly negative. The movement of waste gate 5 towards closed position continues until such time as the balancing effect resulting from the movement of rebalancing slider |09 to the right has been sufficient to overcome the unbalanced condition which initiated the movement of the motor.

The eiect of moving waste gate 6 towards closed position is to result in exhaust gas being forced through the turbine l0 to initiate operation of the supercharger l2. Thus, the pressure of the air supplied to the intake manifold is increased to satisfy the demand of the pressure controller. Thereafter, the waste gate will be adjusted either towards open or towards closed position as is necessary to maintain the pressure at the selected value. Whenever a signal is supplied to the waste gate amplifier 45, a signal is also supplied to the throttle motor ainplier |38 since by reason of the arrangement including the .throttle reset motor |51, the throttle motor amplifier network is kept constantly balanced. If the signal supplied to the two amplifiers is one calling for a higher manifold pressure, the throttle motor |21 will be operated in such a manner as to drive the throttle 5 towards open position. This will again bring Contact |15 into engagement with contact |13, however, and cause energization of the throttle reset motor |51 to move the slider |55 to the left. This signal tends to counteract the signal applied to amplier |38. The throttle reset motor |51 continues to operate and continues to move slider |56 to the left until the change in voltage across the terminals of network |48 is greater than the unbalance voltage which initiated operation of motor |21. When this happens, the throttle motor is operated in the opposite direction to move the contact |13 away from slider |15. Thus, despite the fact that the movement of the slider l5 or the movement of the pressure controller slider 88 in a direction to call for increased manifold pressure, causes operation of the throttle motor even after the throttle is in wide open position, no harm is done since the throttle reset motor merely operates to readjust the balance of the network until the throttle motor amplifier is no longer energized.

It is often desirable to start closing the waste gate some time before the throttle is fully open. In other words, it is desirable to have an overlap between the throttle and waste gate operations. The overlap controller l iii is provided for this purpose. As slider i 5 is moved downwardly, the balance point of the series of networks controlling the energization of amplifier 45 is changed in such a. manner as to cause waste gate E to be closed at a higher manifold pressure or at a less advanced position oi slider E8 than would otherwise vbe the case. It will be noted that the bridge 53 including the overlap controller EEG does not affect the enereization of the thrott e motor amplifier |38. Thus, movement of slider I5 causes the closing of waste gate 5 to take place earlier in the sequence than would otherwise be the case without aiecting the operation ol the throttle controls. This results in an increase in the amount of overlap between the throttle and waste gate operations.

The calibrating potentiometer |55 is provided for the purpose of adjusting the manifold presl l sure. Itwill be clear that the lmovement of the slider .t4 to the rightincreases the manifold pressurethat is maintained for any given setting of the `slider I8. Similarly, a movement of the 'slider St to the left effects a decrease in the value ofthe manifold pressure that is maintained by the system for any given setting of the slider It. The purpose of the acceleration controller is to cause the waste gate to be moved towards open position whenever the accelerationof the turbine becomes excessive. Upon the acceleration exceeding a predetermined value, slider' 95 is 'moved tothe right. This tends to cause conto cause lthe Waste gate to be moved towards open position. Similarly, if the velocity at any time the right. rllhis in turn has a similar elect causing terminal 5l to be made more negative with respect to terminal 52. rThe operation of the calibrated potentiometer 85, the acceleration controller and the velocity controller is more fully described in my (zo-pending application Serial No. 476,797 filed February 22, 1943, now Patent No. 2,477,568,issued August 2, i949.

The operation which has been described so far is that which can take place while the operating lever l5 is in range I. summarizing, vduring this rangeof movement of lever I5, the Setting of the propeller governor is constantly increased to increase the speed of the propeller. Similarly, the setting of the manifold pressure controls are increased to maintain a continually increased manifold pressure. The manifold pressure and propeller speed for any given setting of the lever I5 is `maintained at values dependent upon the position of the lever. When the demand for manifold pressure is relatively low, this is taken care of by an opening movement of throttle 5. As the need for manifold pressure increases-however, the Waste gate S is moved towards closed position to bring the compressor I2 into operation to an increasing extent. During thisfirst range of movement, the air speed controller has not Vbeen adjusted so that it remains inactive.

Upon control lever I5 entering range 2, the engine speed is adjusted in accordance with air speed, as selected by the air speed controller I22. The direct control over the propeller governor 'I by the control lever I5 ceases as the lever reaches range '2 of its movement, as has been pointed out, but the airspeed controller I22 is then advanced by cam 20 and link IM to select a suitable air speed for cruising and like operations. In turn the controller IZZ, through motor 112e and gear train I2 I, positions the propeller governor 'I to select an engine speed known to be best adapted'to that air speed. These are factors determined by the particular engine and aircraft and the cam 2Q is properly selected and formed in order to bring about the adjustment in a precisel and predetermined manner.

The movement' of the control lever I5 through the range 2 has no effect over the controlled intake manifold pressure since the slider I8 is then moving across the conductive dead spot "I3 of potentiometer 69. Thus the balance conditions in the network controlling amplifier l5 are not affected by the movement of the lever and the waste gate 6 is controlled by the pressure controller 97 to maintain aconstant manifoldpressure. AAs the lever is advanced throughfrange 2,

fle itheY wastev gate will "be moved toward the .open :position because theincreased R. P. M. will rev"sult ina greater boost from `the engine driven ablower.

i. 5 VAs the control'lever I5 nowenters and advances 'through range 3V of its adjustment, the throttlel :resetting action' continues as has been described, and the airspeed controller I22 is advanced to increase engine speed further by its control over 'l0 `the propeller governor 'I. At this point, however,

. manual selection of the -intake'manifold pressure yceases as the change-over switch arm 'VI is engagedby the finger 82 on disk Iaand swung into engagement with' iixed contact 19. The circuit .tothe slider I8 is thus broken, and instead conductor 67 (and t5) is connected to the slider 16. SinceV slider i8 is at the potential of the Vleft terminal of resistor 'I when this happens and sinceslider 'It is at the right end of resistor becomes excessive, the slider IBS is moved toward"" mr n0 'abrupt Change in the manifold DTGSSUJ@ occurs. As previously explained the slider It is A.positioned by the controller 126 responsive to propeller or engine'speed, and as the speed in- .creases above a predetermined value, in response 25m-to. the .advance of the control lever l5, controller IZB moves slider 76 from the right hand end of r resistanceV I0 along the resistance at a rate pre- `Aselectedto properly .increase the intake manifold pressure along an optimum operating curve. .The adjustment of slider 76, of course, selects and adjusts the pressure by unbalancing the networks controlling lampliiiers i5 andV I38 in such a manner as to operate either motor 34 or motor 'IE7 to position either vthe waste gate 6 or the 35. throttle as required.

.In summation, it will be evident that advancing the single control lever I5 will resultin an increase in engine speed and power at a certain rate and proportion predetermined and selected .10 accordance with known operating character- .Basically, the control lever rst increases intake manifold pressure and engine speed along j a preselected desirable curve, following the known W optimum line and then positions or sets an air r speed controller which in turn vinstigates the selection of engine power and speed to `maintain theselected air speed regardless of altitude and lother vvarying factors. All this is accomplished without requiring-precise adjustments of sev- UO- eral controls by the pilot, with the attendant possibility that optimum operating conditions would not always be maintained.

The effect of the movement of the control lever r fon engine speed and power is indicated in the 05 chart of Figure 3 and the controls and adjustments responsive to the lever, as it moves through its Ythree ranges, are set out with reference to the corresponding changes in engine speed and power. vThe engine speed and pressure curves as here shown are, of course, only approximate and in practice they will closely follow the opti- `mum power curves as determined by propeller load curves, fuel economy, detonation limits, and .otherv considerations.

'The return movement of the control lever I5 toward starting position will, of course, reverse the actions just described and will reduce both engine speed and intake manifold pressure. lt Hwill be understood that a resetting action of the throttlewill occur during this movement, the

chaser contact I'IZ engaging contact Ile to close vthe circuitv between the inverter |68 and field :winding I of Ythe'motor H57 in order to shift ythezslider V'|55 tothe leftV and supply the ampliffier' I38-with a signalv potential such as to run 17 the floating link 30 back toward the left until the slider |56 finally reaches the right end of re slstor |53.

As is well known in the art there is a pronounced tendency for the air speed of an aircraft to fall off as it makes a turn. Inasmuch as, during the latter portions of the advance movement of control lever l5, the selection of intake manifold pressure and engine speed are instigated by the controller |22 responsive to air speed, it is desirable that any factors materially affecting air speed be overcome.

It is the function of the network 51 to overcome this undesirable effect and compensate the system thereagainst. To this end, the network 51 comprises a transformer having a secondary winding |80 and a primary winding |8I, and the latter is connected to the same source of energy as all the primaries of the other networks. A slidewire resistance |82 is provided and a center tap |83 thereon is connected to one terminal of the secondary winding |89 by a conductor |84. The ends of the resistance |82 are connected to each other by conductors |85 and |86 and are further connected by a conductor |81 to the other end terminal of secondary winding |86. A slider |88 cooperates with the resistance |82 and is connected by a conductor |89 to the lower terminal 6| of the switch 58. The slider 88 is associated with a vertical gyroscope |96 (shown in Figures 1 and 6 in block diagram form) and is positioned with respect to resistance |82 in response to banking of the plane.

The slider |88 is operatively arranged to normally stand at the center of the resistance |82 (Figure 1) but is positioned by gyroscope |96 to move therealong away from such position in opposite directions in response to banking move ment of the plane, or movements thereof about a longitudinal roll axis. rllhis action is illustrated in Figure 2, and since such control operation, per se, is known it will not further be described herein.

Assuming now that the switch arm of switch 58 is operated to close the circuit between its terminals 59 and 6|, it will be evident that the network 51 is then included in circuit between the network 56 and the conductor 61 leading to amplifier input terminals 52 and |45. The circuit may be traced, from the conductor 66, making connection to network 56, through terminals 59 and 6| of the switch 58, conductor |89, the slider |88, center tap |83 of the resistance 82, conductor |85 and a conductor |98 which connects the left hand end terminal of the transformer to conductor 61. Under normal conditions, it will ybe seen then that the network 51 has no effect in the series circuit, since none of the resistance I 82 is in circuit and direct connection is made between the slider |88 and the center tap |83.

However, as the plane banks or rolls, as it will on starting to turn to either side, the slider |88 will, as stated, swing in one direction or another placing a part of the resistance 82 in circuit, the amount depending on the magnitude of the movement of the plane about its roll axis. Assuming the potential conditions which exist during a half cycle at which the ends of the secondary winding |88 are of the polarity indicated, such movement of the slider |88, in either direction, will result in the slider |88 becoming positive with respect to conductor |90. The network 51 under these conditions is thus seen to introduce a potential into the series circuit such that the amplifiers 45 and |38 are provided with signals tending to cause them to operate in such a manner as to increase the manifold pressure. If the throttle is entirely open, the effect of this will be to cause the motor 34 to move the waste gate towards closed position, from whatever position it may have been previously. If the throttle is not fully open, the effect will be to cause the throttle to move towards open position. In either event, the result is a boost in intake manifold pressure and engine power calculated to overcome the tendency toward the reduction in air speed as the aircraft turns. When the turn is completed, the slider |88 returns to normal position, this manifold pressure increasing signal potential is removed, and the selected engine power condition is restored.

Modification of Figure 4 Referring now to Figure 4 of the drawing, I show therein a portion of a control system of a modified form wherein the control of the engine speed and power responsive to selection of air speed is dispensed with. This form of control is perhaps better suited for a pursuit or fighter aircraft, in which extreme maneuverability and flexibility of air speed and engine power are required.

In Figure fi the network 56, control lever |5, change-over switch mechanism 11, propeller speed responsive controller |26 are all exactly as previously described and are accordingly indicated by the same reference characters. However, in lieu of the cams 223 and 2| operated by the lever l5, I have shown a pulley i6! mounted on the shaft |1 and the propeller governor 1 is provided with a similar pulley |92. A cable |83 is trained over the pulleys |9| and |82 and thus the control lever l5 adjusts the governor and the speed of the propeller li throughout the full range of the lever.

In operation of this control system then, it will be apparent that control lever I5 will retain fullcontrol over engine speed, increasing both intake manifold pressure and engine speed as it is advanced. During the mid-range of its movement, however, the control lever will adjust only engine speed until the speed is put in a range which will cause both intake manifold pressure and engine speed to follow the optimum propeller load curve. Thereafter the engine speed will control intake manifold pressure through the controller |26 as has been described.

fication of th-e arrangement shown in Figures 1 and 2. rIhe difference between the arrangement of Figure 5 and that of Figures 1 and 2 is that the switch 11 which transfers control of the manifold pressure from the wiper Hi to the wiper 16 is positioned by the propeller speed responsive controller rather than by the manual lever. Since the elements are all the same with the eX- cep-tion of this difference, the same reference characters have been employed in Figure 5. It will be noted that the switch blade 11 is operative by a cam secured to the output shaft |94 of the speed responsive controller to which is secured the slider 16. When the propeller speed reaches a predetermined value, the cam |95 is rotated in a clockwise direction to move switch blade 11 from engagement with contact 18 into engagement with contact 19.

It will be obvious that with the arrangement of Figure 5, the control of the manifold pressure is la transferred from the manually positioned slider i8 to the propeller speed responsive controller whenever the propeller speed reaches a predetermined value. rlhis value is the one at which slider li first starts moving to the left with respect to resistor lll.

Conclusion It will be apparent that in multi-engine installations of my control system, wherein a separate control lever l is provided for each engine, the speeds of the individual engines may be accurately synchronized, during the time the levers are in range 2 of their movement, by minor adjustments and without affecting intake manifold pressures, optimum cruising conditions and trim may thus be readily attained.

l claim as my invention:

1. An aircraft engine control system for an engine having a throttle, an adjustable means for regulating its intake manifold pressure, and a governor for regulating its speed, comprising in combination, a single manually operable control member movable from minimum power to maximum power positions, means actuated by the control member for opening the throttle as said member is moved toward maximum power position, means actuated by the movement of said control member through a first part of its range for adjusting said intake manifold pressure regulating means, means actuated by movement of said control member through said first part of its range for adjusting the said governor, an air speed selector device, means actuated by the movement of the lever through the latter part of its range for adjusting said air speed selector device, means responsive to adjustment of said air speed selector device for adjusting the said governor, and means responsive to engine speeds selected by such adjustment of the governor for adjusting the said means regulating the intake manifold pressure.

2. In combination with an aircraft engine having a throttle, a supercharger and means regulating the pressure of the air delivered thereby, and a governor regulating the engine speed, a control system comprising a single control lever movable from a minimum power position through three power ranges to a maximum power position,

means actuated by the lever during all power ranges for positioning the throttle, means responsive to movement of the lever through a first power range for controlling said supercharger regulating means, means actuated by the movement of the lever through the said first power range for adjusting the governor, means actuated by movement of the lever through second and last power ranges for continuing the adjustment of the governor, and means responsive to engine speed during the last power range of the lever for continuing the adjustment of the supercharger regulating means.

3. In combination with an aircraft engine having a throttle, a supercharger and means regulating the pressure of the air delivered thereby, and a governor regulating the engine speed, a control system comprising a single control lever movable from a minimum power position through three power ranges to a maximum power position, means actuated by the lever during all power ranges for positioning the throttle, means responsive to movement of the lever only through its first power range for controlling said means regulating the pressure of the air delivered by the supercharger, means responsive to movement Lil() of the lever through its seco-nd and last power ranges for adjusting the governor to increase engine speed, and means responsive to engine speeds selected by the lever during its movement through the last power range for adjusting said means regulating the pressure of the air delivered by the supercharger to increase said pressure proportionately to the engine speed.

4. A control system for an aircraft engine, comprising the combination with an engine having a throttle, a turbo-supercharger including acontrol member controlling the pressure of the air delivered to the intake manifold of the engine, and a propeller governor controlling the engine speed, of a single control lever movable from a minimum power position to a maximum power position, means actuated by the lever throughout its range of movement for positioning the throttle, means responsive to the initial movement of the lever away from minimum power position for adjusting said control meansV to increase intake manifold pressure, means responsive to movement of the lever throughout its range for adjusting the propeller governor to increase engine speed, and means responsive to engine speeds selected during the latter part of the movement of the lever as it approaches maximum power position for adjusting said control member and increasing intake manifold pressure.V

5. A control system for an aircraft engine, comprising the combination with. an engine having a throttle, a compressor including a control membercontrolling the pressure of the air delivered to the intake manifold of the engine, and a propeller governor controlling the engine speed, of a single control lever movable from a minimum power position to a maximum power position, means actuated by the lever throughout its range of movement for positioning the throttle, means responsive to the initial movement of the lever away from minimum power position for adjusting said control means to increase intake manifold pressure, means responsive to movement of the lever only through said initial range for ad-` justing the propeller governor to increase engine speed, an air speed selecting device and means responsive to movement of the lever during the remainder of its range for adjusting said device, means controlled by said device for adjusting the propeller governor to increase engine speed in accordance with selected air speed, and means responsive to engine speeds as selected by said device for adjusting the said control member and increasing intake manifold pressure as required for optimum engine operation at the selected speeds.

6. In combination with an engine having a throttle, a supercharger including a valve member for controlling the intake manifold pressure, and a governor for controlling engine speed, a control system comprising a lever movable from a minimum power position through a plurality of power ranges to a maximum power position, means actuatable by the lever in all ranges for positioning the throttle, electrical means operated by the lever in its movement through. a low power range for positioning the valve member and increasing intake manifold pressure, a control device responsive to engine speed and operative to control said electrical means for positioning the valve member, a transfer switch operative by the lever as it approaches its high power range of movement for transferring control of the valve member from the lever to the said control device, and means operative by the lever for adjusting the said governor.

7. The combination with an internal combustion engine having a throttle and an intake manifold pressure controlling means, a single hand lever movable through a low power range and high power range in succession, said lever being operative in all ranges for positioning the throttle and operative in a low power range for adjusting said intake manifold pressure controlling means, a control device responsive to engine speed and operative to also adjust said controlling means, and means operative by the lever as it approaches its high power range for transferring control of the intake manifold pressure controlling means to said speed responsive control device.

8. The combination with an internal combustion engine having Aa throt/le, a movable control member for controlling the intake manifold pressure, and an engine spec-d controlling governor, of a control lever movable from minimum to maximum power positions, means operative by the lever for positioning the throttle, means operative by movement of the lever through a low power range for positioning said movable control member, means operative by the lever for adjusting said governor, a control device responsive to engine speed and operative also to position said movable control member, and means for transferring control of said movable control member to the said control device as the lever is moved through a high power range.

9. The combination with an internal combustion engine having a throttle, a movable control member for controlling the intake manifold pressure, and an engine speed controlling governor, of a control lever movable from a minimum te a maximum power position, means operative by the lever for positioning the throttle, separate means operative by the lever during its movement thrOugh a lOW DOWer range for adjusting the said movable control member and governor to increase intake manifold pressure and engine speed, a control means controlled by the lever during the balance of its movement toward maximum power position, said control means as it is adjusted by the lever being operative to adjust the governor, and means responsive to the resulting changes in engine speed for positioning the said movable control member and increasing intake manifold pressure in accordance with engine speed.

10. A control system for the throttle, waste gate and propeller governor of an aircraft engine having a turbo-supercharger, comprising in combination, a control lever operative to position the throttle, waste gate and propeller governor, a device for selecting air speeds, means for transferring control of the propeller governor to said device from said lev-er at a predetermined power level, and means responsive to engine speeds as selected by said device for positioning the waste gate and adjusting the intake manifold pressure of the engine proportionately to engine speed.

ll. A control system for the throttle, waste gate and propeller governor of an aircraft engine having a turbo-supercharger, comprising in combination, a control lever movable from minimum to maximum power positions and operative to position the throttle to an open position and adjust the waste gate and propeller governor during a rst range of movement toward maximum power position, an air speed control device adjustable by the lever as it approaches maximum power position, the said propeller governor being adjustable by said control device while same is under control of the lever, and the said lever being adjustable in a medium power range to' control engine speed independently of intake manifold pressure.

12. A control system for the throttle, waste gate and propeller governor of an aircraft engine having a turbo-supercharger, comprising in combination, a control lever movable from minimum to maximum power positions and operative to control the positions of the throttle, waste gate and propeller governor to increase engine power and speed, said lever being mechanically connected to the throttle and propeller governor, the waste gate being controlled by an electrical system having a control resistance and a slider actuated by the said control lever, and said resistance having a portion over which the movement of the slid-er by the control lever will have no effect on waste gate position whereby the control lever may be adjusted to vary engine speed alone.

13. In a control system for an internal combustion engine having a throttle and said system including a single control lever movable from minimum to maximum power positions and operative to increase intake manifold pressures as it is advanced, a throttle adjusting linkage connected between the lever and throttle for opening the same upon an initial advance movement of the lever, said linkage including a floating link, a reset motor means operative to adjust said link in a throttle closing direction, means including an impedance network for controlling said reset motor means, and a variable impedance in such network which is varied upon said throttle being moved to full open position to cause operation of said reset motor means to thereby permit continued advance movements of the lever.`

14. The combination with a control system for an internal combustion engine having a throttle and said system including a control lever operative when advanced to increase engine output, of a mechanism for operating said throttle by the lever, and including a link having a movable fulcrum, motor means for positioning the fulcrum of said link, means including an impedance net- Iwork for controlling said motor means, a variable impedance in said network, and means operative by advance movement of the lever to position opening the throttle to full open position to vary the value of said variable impedance in such a manner as to actuate said motor, means to shift the fulcrum point of the link in a throttle closing direction to thereby permit further advance movement of the lever beyond said position.

l5. The combination with a control system for an internal combustion engine having a throttle and said system including a control lever operative when advanced to increase engine output, of a mechanism for operating said throttle by the lever and including a link having av movable fulcrum, motor means for positioning the fulcrum of said link, means including an impedance network for controlling said motor means, a variable impedance in said network, a second motor for adjusting said variable impedance, and means including chaser contacts operative by the control lever to control the energization of said second motor to cause said iirst named motor means to shift the fulcrum point of the said link.

16. In combination with an aircraft engine having means for varying the quantity of fuel supplied to the engine and a governor'for controlling the speed of a propeller driven by the engine, a device responsive to the speed of said propeller, a manually controlled member, means operated by said manually controlled member for adjusting said governor and for initially adjusting said fuel varying means, means operated by said propeller speed responsive device for adjusting said fuel varying means when the propeller speed reaches a predetermined value.

l'l. In combination with an aircraft engine having means for varying the quantity of fuel supplied to the engine and a governor for controlling the speed of a propeller driven by the engine, a manually positioned member, an electric motor for controlling said fuel quantity varying means, a balanceable impedance network controlling the operation of said motor, said impedance network includingan impedance variable in accordance with a condition ai'lecting the quantity of 'fuel supplied to said engine, adjustable means for varying the operation of said impedance network to vary the quantity of fuel supplied, and mechanical connections between said manually operated member, said propeller' governor, and said adjustable means eictive upon movement of said manually operated member to adjust said propeller governor and to vary the operation of said network.

18. In combination with an aircraft engine having means for varying the quantity of fuel supplied to the engine and a governor for controlling the speed of a propeller driven by the engine, an air speed responsive device, means controlled by said air speed responsive device -lor adjusting said propeller governor, a manually controlled member, means operated by said manually controlled member for adjusting said air speed responsive device and for initially adjusting said fuel varying means, and means operative upon said propeller speed attaining a predetermined value to cause said air speed responsive device to control the adjustment of said fuel varying means.

19. In engine control apparatus for an aircraft engine having valve means for controlling the quantity of fuel delivered thereto and an adjustable propeller governor to control the speed at which a propeller is driven by said engine, a valve positioning member adapted to be connected to such a valve means, a propeller governor adjusting member adapted to be connected to a propeller governor, a manually controlled member connected to said valve positioning member and said propeller governor adjusting member for moving both said positioning member and said adjusting member to maintain a predetermined relation between fuel delivered to the engine and propeller speed, a motor for also moving said valve positioning member, a balanceable impedance network controlling said motor, means responsive to an engine operating variable arranged to control the balance of said network and thencontrol the operation of said motor, and a variable impedance in said network to vary the control point thereof so as to vary the relation between the positions oi said valve positioning and propeller adjusting members.

20. In engine power control apparatus for use with an engine having a combustion chamber, a compressor for supplying air under pressure to the combustion chamber, a device for regulating the compressing effect of said compressor, and a throttle for controlling the flow oi said air to said combustion chamber; a throttle positionving member adapted to be connec'ted to a throttle, a manually controlled member connected to said throttle positioning member, a device positioning member adapted to be connected to a device ior regulating the compressing effect of a compressor, means responsive to an engine operating variable for positioning said throttle positioning member and said device positioning member to cause positioning of the throttle and of the device when operation of the compressor is needed to maintain said operating variable at a selected value, means positioned by said manually controlled member for adjusting said last named operating variable responsive means to vary the value or" the operating variable maintained by it, and independent means for adjusting said operating variable responsive means such a manner that movement of said manually controlled member causes movement of only said throttlepositioning member.

2l. A control system for the throttle and waste gate of an aircraft engine having a turbosupercharger, comprising in combination, a control selector, a device responsive to an engine operating variable, an electrical network having variable impedances included therein, means lincludingv said control selector and said responsive device for variably adjusting said impedances, a first power actuated device for variably positioning the throttle, a second powe-r actuated device 'for variably positioning the waste gate, a first rebalance bridge network having an impedance therein variably adjusted by said first power device, a second rebalance bridge network having an impedance therein variably adjusted by said second power device, rst detecting means for variably energizing said first power device, second detecting means for variably energizing said second power device, and means connecting said rst and second detecting means to be responsive to the electrical balance of said electrical network and said first and second bridges respectively so that said rst and second power devices are energized to maintain electrical balance on their respective detecting means and maintain desired positions of said throttle and waste gate in accordance with the position of said control selector and said responsive device.

22. A control system for the throttle and waste gate of an aircraft engine having a turbo-supercharger, comprising in combination, a control selector, a device responsive to an engine operating variable, a first electrical bridge network having a variable impedance therein, means including said control selector for variably adjusting said impedance, a second electrical bridge network having a second variable impedance therein, means including said responsive device for varying said second impedance, rst and second power actuated devices adapted when energized to variably position the throttle and waste gate respectively, first and second rebalance bridge networks, each having variable impedances therein adjusted by said first and second power devices respectively, means connecting said rst and second electrical bridges and said iirst rebalance bridge in a first series circuit, means connecting said rst and second bridges and said second rebalance bridge in a second series circuit, first and second detecting means for variably energizing said first and second power actuated devices respectively, `and means connecting said iirst and second detecting means to said rst and second series circuits respectively so that said detecting means will energize said respective power actuated devices in accordance with the electrical balance of said series circuits.

23. A control system for the throttle and waste gate of an aircraft engine having a, turbo-supercharger, comprising in combination, a control selector, a device responsive to an engine operating Variable, a iirst electrical bridge network having a variable impedance therein, means including said control selector for variably adjusting said impedance, a second electrical bridge network having a second variable impedance therein, means including said responsive device for varying said second impedance, rst and second power actuated devices adapted when energized to variably position the throttle and waste gate respectively, rst and second rebalance bridge networks each having variable impedances therein adjusted by said nrst and second power devices respectively, means connecting said first and second electrical bridges and said rst rebalance bridge in a rst Series circuit, means connecting said iirst and second bridges and said second rebalance bridge in a second series circuit, i'lrst and second detecting means for variably energizing said first vand second power actuated devices respectively, means connecting said iirst and second detecting means to said rst and second series circuits respectively so that said detecting means will energize said respective power actuated de- 26 vices in accordance with the electrical balance of said series circuits and circuit means within one of said series circuits for causing the electrical balance of said circuit to overlap the electrical balance of the other circuit so that said second power actuated device will variably position said waste gate while said iirst power actuated device is positioning said throttle.

HUBERT T. SPARROW.

REFERENCES CTED Eine following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,998,894 Findley May 16, 1933 2,105,593 Hubbard. Jan. 18, 1938 2,169,194 Bates May 30, 1939 2,209,879 Focke July 30, 1940 2,244,139 Buckingham June 3, 1941 2,398,586 Maddox Apr. 16, 1946 2,428,531 Schorn Oct. 7, 1947 2,437,546 Meripol Mar. 9, 1948 2,480,758 Mock Aug. 30, 1949 2,493,476 Crum et al Jan. 3, 1950 

